1#ifndef BOOST_MP11_DETAIL_MP_COUNT_HPP_INCLUDED
2#define BOOST_MP11_DETAIL_MP_COUNT_HPP_INCLUDED
3
4// Copyright 2015, 2016 Peter Dimov.
5//
6// Distributed under the Boost Software License, Version 1.0.
7//
8// See accompanying file LICENSE_1_0.txt or copy at
9// http://www.boost.org/LICENSE_1_0.txt
10
11#include <boost/mp11/integral.hpp>
12#include <boost/mp11/detail/mp_plus.hpp>
13#include <boost/mp11/detail/config.hpp>
14
15namespace boost
16{
17namespace mp11
18{
19
20// mp_count<L, V>
21namespace detail
22{
23
24#if !defined( BOOST_MP11_NO_CONSTEXPR )
25
26constexpr std::size_t cx_plus()
27{
28 return 0;
29}
30
31template<class T1, class... T> constexpr std::size_t cx_plus(T1 t1, T... t)
32{
33 return static_cast<std::size_t>(t1) + cx_plus(t...);
34}
35
36template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class T10, class... T>
37constexpr std::size_t cx_plus(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7, T8 t8, T9 t9, T10 t10, T... t)
38{
39 return static_cast<std::size_t>(t1 + t2 + t3 + t4 + t5 + t6 + t7 + t8 + t9 + t10) + cx_plus(t...);
40}
41
42#endif
43
44template<class L, class V> struct mp_count_impl;
45
46#if defined( BOOST_MP11_HAS_CXX14_CONSTEXPR )
47
48template<class V, class... T> constexpr std::size_t cx_count()
49{
50 constexpr bool a[] = { false, std::is_same<T, V>::value... };
51
52 std::size_t r = 0;
53
54 for( std::size_t i = 1; i < sizeof...(T) + 1; ++i )
55 {
56 r += a[ i ];
57 }
58
59 return r;
60}
61
62template<template<class...> class L, class... T, class V> struct mp_count_impl<L<T...>, V>
63{
64 using type = mp_size_t<cx_count<V, T...>()>;
65};
66
67#elif !defined( BOOST_MP11_NO_CONSTEXPR )
68
69template<template<class...> class L, class... T, class V> struct mp_count_impl<L<T...>, V>
70{
71 using type = mp_size_t<cx_plus(std::is_same<T, V>::value...)>;
72};
73
74#else
75
76template<template<class...> class L, class... T, class V> struct mp_count_impl<L<T...>, V>
77{
78 using type = mp_size_t<mp_plus<std::is_same<T, V>...>::value>;
79};
80
81#endif
82
83} // namespace detail
84
85template<class L, class V> using mp_count = typename detail::mp_count_impl<L, V>::type;
86
87// mp_count_if<L, P>
88namespace detail
89{
90
91template<class L, template<class...> class P> struct mp_count_if_impl;
92
93#if defined( BOOST_MP11_HAS_CXX14_CONSTEXPR ) && !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
94
95template<template<class...> class P, class... T> constexpr std::size_t cx_count_if()
96{
97 constexpr bool a[] = { false, static_cast<bool>( P<T>::value )... };
98
99 std::size_t r = 0;
100
101 for( std::size_t i = 1; i < sizeof...(T) + 1; ++i )
102 {
103 r += a[ i ];
104 }
105
106 return r;
107}
108
109template<template<class...> class L, class... T, template<class...> class P> struct mp_count_if_impl<L<T...>, P>
110{
111 using type = mp_size_t<cx_count_if<P, T...>()>;
112};
113
114#elif !defined( BOOST_MP11_NO_CONSTEXPR )
115
116template<template<class...> class L, class... T, template<class...> class P> struct mp_count_if_impl<L<T...>, P>
117{
118 using type = mp_size_t<cx_plus(mp_to_bool<P<T>>::value...)>;
119};
120
121#else
122
123template<template<class...> class L, class... T, template<class...> class P> struct mp_count_if_impl<L<T...>, P>
124{
125#if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1920 )
126
127 template<class T> struct _f { using type = mp_to_bool<P<T>>; };
128 using type = mp_size_t<mp_plus<typename _f<T>::type...>::value>;
129
130#else
131
132 using type = mp_size_t<mp_plus<mp_to_bool<P<T>>...>::value>;
133
134#endif
135};
136
137#endif
138
139} // namespace detail
140
141template<class L, template<class...> class P> using mp_count_if = typename detail::mp_count_if_impl<L, P>::type;
142template<class L, class Q> using mp_count_if_q = mp_count_if<L, Q::template fn>;
143
144} // namespace mp11
145} // namespace boost
146
147#endif // #ifndef BOOST_MP11_DETAIL_MP_COUNT_HPP_INCLUDED
148

source code of boost/libs/mp11/include/boost/mp11/detail/mp_count.hpp